Reversible impact driving screw driver



Aprifi 21, 1953 J. F. SPIELMAN REVERSIBLE IMPACT DRIVING SCREW DRIVER Filed April 7, 1952 IN V EN TOR.

Ill-1.4

Patented Apr. 21, 1953 UNITED STATES PATENT OFFICE REVERSIBLE IMPACT DRIVING SCREW DRIVER 5 Claims.

and additionally serves as an ordinary screw- 7 driver. An ordinary screwdriver consists of a handle or body and a working blade.

The word screw shall herein be interpreted as a fastening screw having any type head. The expression working blade shall herein be interpreted to mean any shaft-like portion of a screwdriver for engaging a screwing fastener.

One object of the invention is to provide a screwdriver which transmits the impact of an object upon its handle to a rotative impulse of its working blade.

Another object of the invention is to provide a screwdriver which transmits the impact of an object upon its handle to a rotative impulse of its blade in either direction of rotation a user may select, and which additionally may be adjusted for use as an ordinary screwdriver.

A further object of the invention is to provide a practical, easily assembled design of the invention which will function well in the event of inaccurate mass production of parts.

The foregoing objects of the invention are accomplished in the following description of the accompanying drawing, in which Fig. 1 is a longitudinal partially cross-sectioned view of the inany shape may be used to carry the working parts i of the invention in a cylindrical chamber opening therefrom.

A selector sleeve 8 is round in cross-section,

and is shown having an exterior knurled flange. 5

The selector sleeve 8 is rotatably mounted in the cylindrical interior 1 of the body 6 by a shaftlike retaining pin :8 passing from the body '5 diametricall through the selector sleeve 8 by a pair of diametrically opposite limit slots 19 and l,

zll-(see Fig. 4) through the wall of the selector sleeve 8. The limit slots 19 and 2!! limit the degree to which the selector sleeve 8 may rotate when their ends engage the retaining pin l8.

A shaft-like drive pin 9 is installed diametrically through the selector sleeve 8 at a point near the inward end thereof.

An impact plunger I 0, having a longitudinal cylindrical interior opening to the inward end thereof, is slidably and rotatably mounted in the selector sleeve 8. The retaining pin i 8 passes through the impact plunger Ill by a pair of diamertically opposite compensating spaces 2'! and 28 through the wall of the impact plunger Ill. The compensating spaces 21 and 28 are triangular in plan and diminish symmetrically to apexes toward the interior of the body'B. A pair of diametrically opposite fixing notches I! and 33, located at the named inward-facing apexes of the compensating spaces 2! and 28 respectively, are adapted to slidably receive the retaining pin I8. The impact plunger l0 diminishes in helical symmetry from two diametrically opposite points toward the inward end thereof, providing four helical impact surfaces 23, 24, 25 and 26. The inward extremity of the impact plunger It is faced to provide two diametrically opposite lock flats 29 and 30.

A working blade H is exemplary, and is nonrotatably fixed in and projects outwardly from the substantial radial center of the impact plunger [0. The working blade ll may be permanently fixed in the impact plunger 10, or may be removable and exchangeable with different types of Working blades by a snapping system outside of the invention.

A position piston I2 is slidably and rotatably installed in the impact plunger I0. This is accomplished by the relation of the retaining pin it passing through a diametric aperture through the position piston 12 in the former a pair of diametrically opposite travel slots l6 and 34 which are elongated along the position piston l2. Thus the position piston l2 cannot rotate in relation to the body 5.- The end of the position piston l2 facing thedrive pin 9 contains three adjacent position notches I3, I 4 and I5. The position notches I 3, M and I5 are understood to include their unreferenced diametric opposites because the position piston 12 is not required to be hollow.

A compression spring 31, compressed between the position piston I 2 and the interior of the impact plunger l0, urges the position piston l2 against the drive pin 9 and engages the fixing notches l1 and 33 with the retaining pin l8.

As illustrated in Figs. 1 and 2 the invention is in a neutral position, and may be used as an ordinary screwdriver. The point of the working blade H may be engaged in the slot of a type of screw. Subsequent manual rotation of the body 6 is transmitted to the impact plunger l0 and to the working blade II by engagement of the retaining pin 18 against either side of the fixing notches I! and 33. The retaining pin it 3 is prevented from leaving the fixing notches I1 and 33 because the drive pin 9, nesting in the diametric position notch M in the position piston l2, abuts the lock flats 29 and 3.0 on the impact plunger 10. The invention is now seen to be efiective as an ordinary screwdriver.

With the components of the invention thus described, the impact operation of the invention may be readily seen when Figs. 2 and 3 are observed. When the body 6 is held in its position (Fig. 2), the selector sleeve 8 may be rotated to move an indicating mark 32 (Fig. 1) toward the loosening position L until the ends of the limit slots [9 and 20 (Fig. 4) engage the retaining pin [8. During this adjusting movement, the drive pin -9 slightly compresses the position piston 12 into the impact plunger 10 against the tension of the compression spring 3| and enters the diametric position notch l3 in the position piston l2 .(see dotted lines, Fig. Sliding movement of the position piston 12 is permitted by'the elongated travel slots Hi and 34 therethrough.

When the indicating mark '32 :is at the position L, the drive pin '9 is no longer aligned over the lock flats 29 and .30. A user may now insert the point of the working blade H in the :slot of a type of screw (not shown), may grip the body tightly, and may strike a blow upon the top (as illustrated) of the body 6 with the palm of his hand or with some inanimate object. The effect of this impact is seen in Fig. 3 where the drive pin 9 has forcefully engaged the incline of the helical impact surfaces 23 and 25, increasing the force of engagement of the point of the working blade II with the screw and simultaneously transmitting a rotative loosenin impulse to the screw, assuming that the screw has a right-hand thread.

During operational impact movement, the retaming pin 1-8 travels freely along a centering edge 22 of the compensating space .21 and along a similar centering edge of the compensating space 28. At the same time, drive pin '9 forces the position piston 12 into the impact plunger against the tension of the compression spring 3|.

After an operational impact, the compression spring 8| reacts, bringing the retaining pin t8 again into the fixing notches l7 and 33 by the guiding effect of the'centeringedge 2i and asimila-r centering edge of compensating space 2-8.

It becomes evident here that adjustment of the indicating mark 32 to the position T (Fig. 1) reverses the direction of rotative impulse upon operational impact. At this reverse or tightening adjustment, the drive pin 9, nesting in the position notch 15, encounters the reverse orcountor-inclining impact surfaces 24 and 26 during impact operation. Centering edge 21 and acooperating centering edge of the compensating space 28 return the retaining pin l8 to the firing notches I1 and 33. Examination of the drawings reveals that no force of impact or return tends to upset the settings on L and T. The direction of operational rotative impulse is-seen to be controlled by adjustment of the drive pin 9 in a plane beyond the inward-facing end of the impact plunger l0.

The invention will perform well in the face of inaccurate mass production for the following reasons: A drive pin contacting any one of the impact surfaces 23, 24, 25 or 26 will provide the desired rotative impulse. Similarly, any one centering edge of the compensating spaces 2'! and 28 will guide the retaining pin [8 to the deacti- 4 vated position. Thus tolerances for fitting of the parts together are suitable for systematic mass production.

The foregoing description has closely :followed the illustrated practical or ideal design of the invention. However, there lies in the invention a spirit and principle of operation which might be duplicated by variation of parts unless point- :ed out herein. The following circumstances are seen to exist when the accompanying drawing is examined: The drive pin 9 operates specifically in relation to the lock flats 29 and 30, the helical impact surfaces 23, 24, and 26, and the position-notches l3, l4 and I5, permitting these named cooperating features of the invention to be rotated as one from alignment with the retaining pin 18 as illustrated. The fixing notches H and 33 are not necessaril required for operation as an ordinary screwdriver, provided that the lock flats '29 and include large enough segments of the circular extremity of the impact plunger 40 to prevent a sliding movement of the impact plunger lfi'when the drive pin is nesting in the position notch 14. The invention may then be interpreted in the following claims.

Iclaim:

1. A reversible impact driving screwdriver "comprising basically :a body and a working blade, the body portion of said screwdriverembodying therein a slidable and rotatable impact plunger, said impact plunger having an interior opening to an inward-facing end thereof, said impact plunger having a diam'etricspace through an intermediate point between the ends thereof, said space having an apex toward the inward-facing end of said impact plunger, said impact plunger diminishing in helical symmetry from two diametrically opposite points toward the inwardfacing end thereof to the inward-facing end thereof whereby the inward-facing extremity thereof comprises a pair of diametrically opposite fiats, said impact plunger having means on the outward-facing end thereof for non-rotatably carrying the screwdriver working blade, said screwdriver further embodying a shaft-like retaining pin passing from the body thereof diametrically through the said impact plunger by way of the said diametric space therethrough, said screwdriver further embodying an externally operable shaft-like drive pin diametrically disposed relative to the said impact plunger and adjustable by hand to a limited degree in a plane .beyond the inward-facing end of the said impact plunger, whereby the distance between the said retaining pin and the said drive pin is in prac tice normally slightly greater than the distance between the said fiats comprising the inwardfacing extremity of the said impact plunger and the said apex of the said diametric space through the said impact plunger, and whereby an intermediate adjustment of the said drive pin in the said .plane beyond the inward-facing end of the said impact plunger aligns said drive pin with the said diametrically opposite flats comprising the inward-facing extremity of the said impact plunger.

2. A reversible impact driving screwdriver, said screwdriver comprising a body, said body having a cylindrical interior opening therefrom, a selector sleeve rotatably mounted inthe said cylindrical interior of said body, said selector sleeve having a portion thereof projecting from said body, said selector sleeve containing a pair of diametrically opposite peripherally extending limit slots through the Wall thereof at an intermediate point thereon, a drive pin carried diametrically across the inward end of said selector sleeve, an impact plunger slidably and rotatably mounted in said selector sleeve, said impact plunger having means on the outward-facing end thereof for non-rotatably mounting a screwdriver working blade thereon, said impact plunger having a cylindrical nterior opening toward the inward end thereof, said impact plunger having a diametric compensating space therethrough, said compensating pace diminishing in helical symmetry to an apex toward the inward end of said impact plunger, said impact plunger diminishing in helical symmetry from two diametrically opposite points thereon to the inward extremity thereof whereby to provide a pair of diametrically opposite lock flats at the inward extremity thereof, a position piston slidably and rotatably mounted in the inward end of said impact plunger, said position piston containing three diametric position notches on the end thereof adjacent to said drive pin across said selector sleeve, said position piston having a diametric aperture therethrough, said diametric aperture being elongated lengthwise relative to said position piston, a compression spring compressed between the interior of said impact plunger and said position piston whereby said position piston is urged against said drive pin and said impact plunger is urged outwardly from said selector sleeve, and a retaining pin passing diametrically from said body through said selector sleeve by way of said pair of limit slots, through said impact plunger by way of said compensating space, and through said position piston by way of said diametric aperture therethrough, whereby the distance between said drive pin and said retaining pin is slightly greater than the distance between the inward extremity of said impact plunger and the said compensating space apex facing the inward end of said impact plunger.

3. A reversible impact driving screwdriver, said screwdriver comprising a body, said body having a cylindrical interior opening therefrom, a selector sleeve rotatably mounted in the said cylindrical interior of said body, said selector sleeve having a portion thereof projecting from said body, said selector sleeve containing a pair of diametrically opposite peripherally extending limit slots through the wall thereof at an intermediate point thereon, a drive pin carried diametrically across the inward end of said selector sleeve, an impact plunger slidably and rotatably mounted in said selector sleeve, said impact plunger having means on the outward-facing end thereof for non-rotatably mounting a screwdriver working blade thereon, said impact plunger having a hollow portion opening to the inward end thereof, said impact plunger having a diametric compensating space therethrough, said compensating space diminishing in helical symmetry to an apex toward the inward end of said impact plunger, said impact plunger diminishing in helical symmetry from two diametrically opposite points thereon to the inward extremity thereof, a position piston longitudinally slidable within and rotatable with said body and urged against said drive pin across said selector sleeve by spring tension, said position piston containing three diametric position notches on the end thereof adjacent to said drive pin across said selector sleeve, a compression spring carried in the said hollow portion opening to the inward end of said impact plunger and compressed mechanically between said impact plunger and said body member whereby to urge said impact plunger outwardly from said selector sleeve, and a retaining pin passing diametrically from said body through said selector sleeve by said pair of diametrically opposite limit slots and through said impact plunger by said compensating space therethrough, whereby the distance between said drive pin and said retaining pin is slightly greater than the distance between the inward extremity of said impact plunger and the said compensating space apex facing the inward end of said impact plunger.

4. A reversible impact driving screwdriver comprising basically a body member and a working blade member, the body member of said screwdriver carrying therein a slidable and rotatable impact plunger, said impact plunger non-rotatably carrying the said working blade member at a first end thereof, said impact plunger having an interior space toward and opening to a second end thereof, said impact plunger having a compensating space at an intermediate point between the said first and second ends thereof, said compensating space having an apex toward the said second end of said impact plunger, the said second end of said impact plunger embodying a system of counter-inclining impact surfaces, wherein a drive pin means adjustable to a limited degree in a plane beyond the said second end of said impact plunger is carried for engaging said system of counter-inclining impact surfaces during operative impact, and wherein a pinning member projects from said body member to normally engage the said apex of said compensating space in said impact plunger.

5. A reversible impact driving screwdriver comprising basically a body member and a working blade member, the body member of said screwdriver carrying therein a slidable and rotatable impact plunger, said impact plunger non-rotatably carrying the said working blade member at a first end thereof, said impact plunger embodying a system of counter-inclining impact surfaces at a second nd thereof, said impact plunger embodying a system of counter-inclining centering edges at an intermediate point between the said first and second ends thereof, said centering edges converging to an apex facing toward the said second end of said impact plunger, wherein a driving means adjustable to a limited degree in aplane beyond the said second end of said impact plunger is carried for engaging said system of counter-inclining impact surfaces during operative impact, and wherein an element extends from said body member to normally engage the said apex of said counter-inclining centering edges.

JAMES F. SPIELMAN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,743,505 Turgeon Jan. 14, 1930 2,010,616 Walsh Aug. 6, 1935 2,219,865 Fitch Oct. 29, 1940 2,543,441 Crummey Feb. 27, 1951 FOREIGN PATENTS Number Country Date 343,400 Italy Sept. 28, 1936 429,810 Italy Feb. 3, 1948 810,739 Germany Aug. 13, 1951 

